diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 8c0c376c8e0d95f7a88a3af8b181202a8d036e20..6627b3d2fce1edff3ecd24b21919dbc8b6282fb8 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -39,16 +39,6 @@ abstract class ConfigEntityBase extends Entity implements ConfigEntityInterface
    */
   protected $originalId;
 
-  /**
-   * The name of the property that is used to store plugin configuration.
-   *
-   * This is needed when the entity uses a LazyPluginCollection, to dictate
-   * where the plugin configuration should be stored.
-   *
-   * @var string
-   */
-  protected $pluginConfigKey;
-
   /**
    * The enabled/disabled status of the configuration entity.
    *